A wide variety of medical techniques and instruments have been developed for diagnosis as well as treatment within the body of a patient, such as in the gastrointestinal (GI) tract. Medical procedures, including Endoscopic Mucosal Resection (EMR), Endoscopic Sub-mucosal Resection (ESR), Polypectomy, Mucosectomy, etc., are minimally invasive methods for severing and retrieving malignant and non-malignant lesions, e.g., polyps. Procedures such as, EMR involve resection of a lesion or unwanted tissue from a tissue wall within a body lumen. Snares have been commonly used during such medical procedures for resecting tissue from a target site. During resection procedures, physicians ensnare or capture a target tissue within a loop of the snare. Often, a physician may apply a downward force on the snare in an effort to improve snare traction around the target tissue and resect the target tissue closer to its base on the tissue wall. However, when such a downward force is applied, a distal portion of conventional snares have a tendency to deflect away from the tissue wall. Such snares may be stiff and may have insufficient traction on the tissue, and often require repeated efforts to resect the tissue before the procedure can be successfully completed. Stiffness may lead to deflection of the snare from the tissue wall, (e.g., deflection away from a tissue plane defined by the tissue wall). Also, deflection of the snare before resection can lead to an “angled cut” instead of an “even cut” (e.g., a cut substantially parallel to or coplanar with the tissue plane). As such, conventional snares conform poorly to the tissue plane during resection.
Furthermore, conventional snares often include a snare loop of uniform cross-section. As noted above, such snares tend to be stiff and deflect away from the tissue plane during resection. Additionally, the performance of such snares may suffer. For example, in embodiments employing electrosurgical energy, a uniform cross-section snare loop may include a greater surface area than a snare with a varied cross-section. A greater surface area may result in reduced current density delivered to the target tissue during cutting. Additionally, conventional thick (e.g., uniform cross-section) snare loops, due to their inherent stiffness, often require greater force to extend and retract the snare loop during a procedure, thereby reducing the smoothness and/or responsiveness of actuation by a physician. This, likewise, limits the geometry of the loop itself, since a round, open snare loop requires greater deformation in order to be drawn into a snare sheath, and stiff, opposing sides of the snare loop tend to twist away from the tissue plane during extension and refraction. Indeed, an excessively stiff snare loop can also increase risk of unintended tissue trauma and perforation.
A tool or device with increased flexibility and control for better functional performance and improved traction may provide consistent capture, excision, and/or removal of unwanted tissue without unintentionally damaging healthy surrounding tissue.
The exemplary features of the present disclosure are directed to improvements in tissue resection devices and methods.
Embodiments of the present disclosure relate to medical devices and methods for performing tissue resection.
In accordance with an aspect of the present disclosure, the medical device may include a snare member having a proximal portion and a distal portion. The medical device may also include an operating member extending proximally of the snare member. The operating member may be enabled to extend and retract the snare member. Further, the snare member may include a transition portion extending between the proximal portion and the distal portion. The transition portion may connect the proximal portion to the distal portion, wherein the distal portion may have a different cross-sectional area than the proximal section of the snare member.
The medical device may further include one or more of the following features: the cross-sectional area of the distal portion may be smaller than the cross-sectional area of the proximal portion and the cross-sectional shape of the distal portion may be circular and the cross-sectional shape of the proximal portion may be non-circular; at least one traction member that may extend along a first portion of the snare member, wherein the at least one fraction member may be a continuous spiral coiled around the first portion of the snare member; the at least one traction member may be a first traction member and the medical device may further include a second traction member extending along a second portion of the snare member opposite the first portion of the snare member, the second traction member may be a continuous spiral coiled around the second portion of the snare member; a plurality of traction members may be formed of a continuous piece of material with the snare member, wherein each of the plurality of traction members may be spaced from an adjacent traction member of the plurality of tractions members and may be configured to extend radially outwardly from the snare member; each of the plurality of traction members may have a cross-sectional shape selected from the following: rectangular, semi-circular, ovular, and polygonal, and wherein a first series of traction members is disposed on a first portion of the snare member and a second series of traction members is disposed on a second portion of the snare member opposite the first portion of the snare member; at least one of the plurality of traction members may have a different cross-sectional shape than at least one other of the plurality of traction members; and each of the plurality of the traction members may extend in the same direction outward from the snare member.
In accordance with another aspect of the present disclosure, a medical device may include a snare member having a proximal portion and a distal portion. The medical device may also include an operating member extending proximally of the snare member. The operating member may be configured to extend and retract the snare member. The snare member may include a transition portion extending between the proximal portion and the distal portion, connecting the proximal portion to the distal portion. The distal portion may be more flexible than the proximal section of the snare member.
The medical device may further include one or more of the following features: a cross-sectional area of the distal portion may be smaller than a cross-sectional area of the proximal portion, and a cross-sectional shape of the distal portion may be circular and a cross-sectional shape of the proximal portion may be non-circular; at least one traction member may extend along a first portion of the snare member, wherein the at least one fraction member may be a continuous spiral coiled around the first portion of the snare member; the at least one traction member may be a first traction member, the medical device may further include a second traction member which may extend along a second portion of the snare member opposite the first portion of the snare member, the second traction member may be a continuous spiral coiled around the second portion of the snare member; a plurality of traction members may be formed of a continuous piece of material with the snare member, each of the plurality of traction members may be spaced from an adjacent traction member of the plurality of traction members and may be configured to extend radially outwardly from the snare member; each of the plurality of the fraction members may have a cross-sectional shape selected from the following: rectangular, square, semi-circular, ovular, and polygonal, and a first series of traction members may be disposed on a first portion of the snare member and a second series of fraction members may be disposed on a second portion of the snare member opposite the first portion of the snare member; and at least one of the plurality of traction members may have a different cross-sectional shape than at least one other of the plurality of traction members.
In accordance with another aspect of the present disclosure, a method of forming a medical device may include forming a loop of a snare member. The snare member may have a proximal portion and a distal portion. The method may further include modifying the snare member to form a transition portion extending between the proximal portion and the distal portion. The transitional portion may connect the proximal portion to the distal portion. Modifying the snare member may include altering a cross-sectional area of the distal portion so as to be different than the cross-sectional area of the proximal portion.
The method may further include one or more of the following features: the cross-sectional area of the distal portion may be smaller than the cross sectional area of the proximal portion, and a cross-sectional shape of the distal portion may be circular and a cross-sectional shape of the proximal portion may be non-circular; forming at least first and second traction members, the first fraction member may extend along a first portion of the snare member, wherein the first traction member may be a continuous spiral coiled about the first portion of the snare member, the second traction member may extend along a second portion of the snare member opposite the first portion of the snare member, and the second traction member may be a continuous spiral coiled about the second portion of the snare member; forming a plurality of traction members which may be of a continuous piece of material with the snare member, each of the plurality of traction members may be spaced from an adjacent fraction member of the plurality of traction members and may be configured to extend radially outwardly from the snare member; and each of the plurality of the fraction members may have a cross-sectional shape selected from the following: rectangular, square, semi-circular, ovular, and polygonal, and a first series of traction members may be disposed on a first portion of the snare member and a second series of traction members may be disposed on a second portion of the snare member opposite the first portion of the snare member.
Additional objects and advantages of the present disclosure will be set forth in part in the description which follows, and in part will be understood from the description, or may be learned by practice of the claimed features. The objects and advantages of the claimed features will be realized and attained by means of the elements and combinations particularly pointed out in the appended claims.
It is to be understood that both the foregoing general description and the following detailed description are exemplary and explanatory only and are not restrictive of the disclosure, as claimed